Question 1

Which of the following holds the highest levels of oxygen?

Accepted Answer

Cold water holds more oxygen than warm water, and flowing water holds more oxygen than still water. Therefore, the cold flowing water in the stream in Ontario in April is likely to hold the highest levels of oxygen.

Question 2

Water that comes up positive after fecal coliform testing indicates health risks most commonly associated with

Accepted Answer

Fecal coliform testing specifically looks for bacteria that are associated with human and animal waste. Therefore, if water comes up positive after fecal coliform testing, it is most likely contaminated with pathogens commonly found in human sewage.

Question 3

On average in the United States,every day each person produces about

Accepted Answer

On average, each person in the United States produces about 150-200 gallons of wastewater daily, but the actual waste content is less than a half gallon. This high volume of wastewater includes all water used in households for various purposes, such as bathing, toilet flushing, laundry, and dishwashing, with a relatively small proportion being actual waste.

Question 4

If you collect a jar of muddy water from a puddle or ditch,and then let the mud settle out over many hours,you have separated much of the mud from the water using a process very much like the

Accepted Answer

The process described is similar to the primary treatment in a wastewater facility, where solids settle out in a sedimentation tank. The mud settling out from the jar of muddy water is analogous to solids settling out in the sedimentation tank, leaving behind cleaner water.

Question 5

Anaerobic conditions will most likely be generated in a natural water system with

Accepted Answer

Anaerobic conditions are typically associated with low levels of dissolved oxygen (DO). Pollutants with high biological oxygen demand (BOD) values consume the available DO, leading to anaerobic conditions. Therefore, in a natural water system, low levels of DO contaminated by pollutants with high BOD values are most likely to generate anaerobic conditions.

Question 6

The fecal coliform test is used to determine if the water being tested could transmit

Accepted Answer

Fecal coliforms are bacteria found in the intestines of warm-blooded animals, including humans. Their presence in water indicates a risk of contamination by human or animal waste, which could contain harmful pathogens that cause diseases such as dysentery and cholera. Therefore, the fecal coliform test is used to determine if the water being tested could transmit these diseases.

Question 7

-This small residential pond in the middle of this subdivision is most likely

Accepted Answer

Small residential ponds are often designed as part of storm-water management systems. They help to manage runoff, reduce erosion, and improve water quality by allowing sediments and pollutants to settle before the water is released into larger bodies of water or the groundwater system.

Question 8

The carrot peelings you send down a garbage disposal represent which of the following types of wastewater pollutant?

Accepted Answer

Carrot peelings are solid, organic materials that do not dissolve in water, making them particulate organic matter. This type of waste contributes to the organic load in wastewater and requires physical and biological treatment processes for removal.

Question 9

A farmer extending his farm field bulldozes the banks of a creek,greatly disturbing the creek bed and stirring up clay and humus.The higher levels of clay and humus in the water just downstream will most likely result in

Accepted Answer

Bulldozing the creek banks and disturbing the creek bed will increase the turbidity of the water, making it cloudy. The higher levels of clay and humus in the water are likely to reduce the amount of light that penetrates the water, making it difficult for plants to grow. The reduced light penetration and increased turbidity can also reduce the oxygen level in the creek and lead to a decrease in fish populations. Therefore, the most likely outcome is fewer plants, fewer fish, and cloudy water.

Question 10

Biochemical oxygen demanding wastes (BOD)include

Accepted Answer

Biochemical oxygen demanding wastes (BOD) refer to organic biodegradable material that requires oxygen to be decomposed by bacteria. This includes human and animal waste, food waste, and other organic material. Phosphorus and nitrogen-based fertilizers (A) contribute to nutrient pollution in water, while sand, silt, and clay suspended in water (B) can cause sedimentation and turbidity. Fish, aquatic insects, algae, and other live aquatic organisms (C) are not considered BOD waste, as they are naturally occurring in aquatic environments.

Question 11

Some people become alarmed when they learn that the water they drink contains known carcinogens.These concerned people

Accepted Answer

The presence of carcinogens in drinking water is a concern, but the concentration of these carcinogens in the water is what determines the degree of risk. Therefore, it is important for concerned individuals to understand the concentration levels of the carcinogens in their drinking water before becoming overly alarmed.

Question 12

About 100 meters downstream of a raw sewage discharge outlet we would expect to find

Accepted Answer

Raw sewage discharge contains high levels of organic matter, which causes an increase in bacteria that consume oxygen when they decompose it. This process leads to a depletion of dissolved oxygen in the water, making it unsuitable for most aquatic life. Additionally, the presence of high levels of nutrients like nitrogen and phosphorus can create an overgrowth of algae, resulting in cloudy water. Therefore, we would expect to find cloudy water, low levels of oxygen, and few, if any, fish downstream of a raw sewage discharge outlet.

Question 13

In general,the strictest standards with the lowest acceptable levels are the

Accepted Answer

Maximum contaminant levels are typically the strictest standards with the lowest acceptable levels, as they are based on potential health risks and set by the EPA. Criterion continuous concentration values and criteria maximum concentration values also involve setting acceptable levels for pollutants, but they may not be as strict as maximum contaminant levels in terms of protecting human health. Standards for saltwater systems are specific to aquatic systems and may not apply to other environments.

Question 14

-The method illustrated in these figures is testing water for

Accepted Answer

The method shown is likely testing for bacterial contamination, as water quality tests for bacteria (such as E. coli or coliforms) are common to assess the safety of drinking water or recreational waters. Testing for eutrophicant fertilizers, fungal infections, or oxygen levels involves different methodologies and equipment.

Question 15

What stage of wastewater treatment would remove a condom that had improperly been flushed down a toilet?

Accepted Answer

The stage of wastewater treatment that focuses on the removal of debris such as plastics, condoms, and other large objects is called debris removal. This stage is usually the first step in the treatment process and involves the use of screens and grit chambers to remove large objects and particles from the water. Therefore, the removal of a condom that was improperly flushed down a toilet would occur in the debris removal stage.

Question 16

Homeowners living in a heavily forested region surrounding a small 3-acre pond in Missouri decided to reduce air pollution in their neighborhood.In the fall,after the oak and maple leaves had fallen,the homeowners blew all of the dead leaves into the pond.About 8 months later,in July,they noticed a large number of dead fish in the pond.What is the most likely cause of the fish kill?

Accepted Answer

The most likely cause of the fish kill is that the bacteria decomposing the leaves depleted the levels of oxygen in the water. As the leaves decompose, they consume oxygen, which can lead to oxygen depletion in the water. This can cause fish and other aquatic animals to suffocate and die.

Question 17

Although you should not flush a used condom down a toilet,if a person did,this type of wastewater pollutant would represent

Accepted Answer

The answer of Although you should not flush a used...

Question 18

A new gravel road is cut into the side of a mountain just north of Anchorage,Alaska.As the snow melts in June,the fine gravel and sand of the disturbed region quickly tumbles into the bottom of nearby streams.The addition of this fine gravel and sand changes the stream by

Accepted Answer

The addition of fine gravel and sand into streams can cover habitats and reduce water clarity, negatively affecting both plant and animal life by decreasing their numbers.

Question 19

In downtown Philadelphia,water in storm drains most likely came from

Accepted Answer

Storm drains are designed to collect rainwater, so the most likely source of water in storm drains would be from precipitation that falls onto surfaces such as lawns, streets, and sidewalks. Water from sinks, toilets, and bathroom showers typically drains to the city's wastewater treatment plant, not the storm drain system.

Question 20

In 2007,heavy rains accompanied an outbreak of cholera in children living in war-torn Iraq.What was the likely cause of the spread of this disease?

Accepted Answer

The most likely cause of the spread of cholera in this scenario would be pollution of waterways by raw sewage. Heavy rains could cause sewage to overflow into water sources, contaminating them and making them dangerous to drink. Cholera is a water-borne disease, so polluted water sources are a common cause of outbreaks.

Quiz 20: Water Pollution and Its Prevention